CN110470426A - A kind of fiber-optic grating sensor and measurement method that can measure temperature and pressure simultaneously - Google Patents
A kind of fiber-optic grating sensor and measurement method that can measure temperature and pressure simultaneously Download PDFInfo
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- CN110470426A CN110470426A CN201910771851.9A CN201910771851A CN110470426A CN 110470426 A CN110470426 A CN 110470426A CN 201910771851 A CN201910771851 A CN 201910771851A CN 110470426 A CN110470426 A CN 110470426A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
- G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
- G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/04—Means for compensating for effects of changes of temperature, i.e. other than electric compensation
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Abstract
The invention discloses fiber-optic grating sensor and measurement method that one kind can measure temperature and pressure simultaneously, which includes the thin wall cylinder of bottom opening, the protection shell being encapsulated in outside thin wall cylinder, and there are gaps between the thin wall cylinder and protection shell；The thin wall cylinder outer surface is fixed with the first fiber grating and the second fiber grating, the optical fiber pigtail of first and second fiber grating is pierced by the top of protection shell, the cross section of the thin wall cylinder is the class ellipse surrounded by two straight lines with two semi arches for being separately connected two straight line both ends, the center in face where first fiber grating is fixed on the straight line of thin wall cylinder along thin wall cylinder axis direction, the center in face where second fiber grating is fixed on the semi arch of thin wall cylinder along thin wall cylinder axis direction, and first and second fiber grating center and the center of thin wall cylinder be located on sustained height, sensor structure disclosed in this invention is novel, high sensitivity, measurement result is reliable, using wide.
Description
Technical field
The present invention relates to a kind of fiber-optic grating sensor, in particular to a kind of optical fiber light that can measure temperature and pressure simultaneously
Gate sensor and measurement method.
Background technique
Pressure is an important physical parameter, and in ocean, national defence, petrochemical industry, medical treatment, aviation, the fields such as electric power have emphatically
The measurement value wanted.By pressure measurement, we will be seen that the safe condition of equipment, the operating status of system, the change of environment
Change the depth etc. of situation and a certain position of undersea.Existing pressure sensor is mostly that electric-type sensor makes in electromagnetism interference
With safety, there are some problems for signal transmits at a distance etc., thus in strong electromagnetic, it is inflammable and explosive, it is remote to join
The occasions such as number monitoring use limited.And the fibre optic compression sensor based on optical signal, the intrinsic safety of existing sensor, and can
Realize signal it is remote transmit and it is interference-free.
Existing frequently-used fibre optic compression sensor mainly has fiber Bragg grating type pressure sensor and optical fiber Fabry Perot formula
Pressure sensor.Optical fiber Fabry Perot formula pressure sensor volume is smaller, structure is simple, is usually used in single-point type pressure measurement,
But be not suitable for the distributed measurement of sensor.Fiber grating is the stable fiber optic sensing device of a kind of technical maturity, performance, and light
Fiber grating sensor is convenient for distributed measurement, has extensive application in actual production and life.Due to the pressure of fiber grating itself
Force sensitivity is lower (only about 0.003nm/MPa), and in order to realize the pressure measurement of high resolution, many relevant design schemes are borrowed
Different sensitization structures improves the sensitivity of fibre optic compression sensor.Existing pressure sensitization structure has diaphragm type, thin wall cylinder
The structures such as formula, polymer overmold formula and spring-tube type.However, diaphragm type pressure sensor generally requires complexed metalization encapsulation,
Manufacture craft is more complicated, and cost is relatively high；Spring-tube type grating pressure sensor needs the reliable fit between part, otherwise holds
Easily there is Zero drift in main amplifier；Then there is aging and creep problem when used for a long time in polymer pressure sensor.
Shen Rensheng of Dalian University of Technology et al. has invented a kind of fiber bragg grating pressure sensor (ginseng of thin-walled strain cartridge type
Examine patent: inner arced ceiling thin wall straining cartridge throw-in type optical fibre Bragg grating pressure sensor, publication number: CN101266179), this
Kind sensor is made of metal thin-wall inner cylinder, metal thick wall outer cylinder, pressure measuring gratings, temperature compensation grating and gasket.According to text
The cross section of middle statement, this kind of sensor metal thin-wall inner cylinder is circle, and pressure-sensitivity is only 0.033nm/MPa, is being applied
Meet demand is unable to when some sensitivity requirements higher occasion.In addition, temperature compensation grating is fixed on thin-wall circular in the program
The top of cylinder, and pressure grating is axially fixed on the outside of barrel along thin wall cylinder, because two fiber grating dimensional orientations are vertical, away from
From farther out, causing two grating present position temperature gradients excessive, the decoupling response time is too long, and is located at thin wall cylinder top outer
Temperature compensation grating is easy the interference by ambient temperature.
Summary of the invention
In order to solve the above technical problems, the present invention provides the optical fiber grating sensings that one kind can measure temperature and pressure simultaneously
Device and measurement method, high sensitivity, temperature-responsive is fast, watertightness is good, and structure is simple, can be applied to pipeline pressure, sea water advanced
The measurement of (pressure) etc..
In order to achieve the above objectives, technical scheme is as follows:
A kind of fiber-optic grating sensor that can measure temperature and pressure simultaneously, thin wall cylinder including bottom opening are encapsulated in
Protection shell outside thin wall cylinder, there are gaps between the thin wall cylinder and protection shell；The thin wall cylinder outer surface is fixed with
It is outer that the optical fiber pigtail of first fiber grating and the second fiber grating, first fiber grating and the second fiber grating is pierced by protection
The top of shell, the cross section of the thin wall cylinder are by two straight lines and two semi arches for being separately connected two straight line both ends
The class ellipse surrounded, face where first fiber grating is fixed on the straight line of thin wall cylinder along the axis direction of thin wall cylinder
Center, the center in face where second fiber grating is fixed on the semi arch of thin wall cylinder along the axis direction of thin wall cylinder, and the
The center at the center and thin wall cylinder of one fiber grating and the second fiber grating is located on sustained height.
In above scheme, the thin wall cylinder bottom outer-edge is connected with annular fixed disk, outside the protection outer casing bottom
Edge is groove structure, and the annular fixed disk is embedded in the groove, and is bolted between the two, and the annular is fixed
Pressure fixing hole is opened up in disk and protection outer casing bottom outer rim same position, sensor can be fixed on pressure checking with bolt
Test on platform, for sensor.
In above scheme, the protection cover top portion opens up threaded hole, and the threaded hole bottom is opened up to be joined with the gap
Logical tail optical fiber fairlead, has been connected through a screw thread pressing device in the threaded hole, the pressing device and threaded hole bottom it
Between be equipped with graphite sealing gasket, the pressing device rear end is by connecting sleeve connection tail bone pipe, and the optical fiber pigtail is from tail optical fiber
It is pierced by fairlead, sequentially passes through graphite sealing gasket, pressing device, connecting sleeve and tail bone pipe.Tail cone pipe is for optical fiber
It draws and can prevent excessive fiber bending from fiberoptic light transmission loss being caused to increase.
It is matched by using graphite sealing gasket with pressing device, effective sealing to tail optical fiber fairlead may be implemented.
Its principle be with pressing device to graphite sealing gasket applied force when, will lead to graphite sealing gasket, deformation occurs, Jin Ershi
Ink is full of tail optical fiber fairlead, realizes the sealing to tail optical fiber fairlead.
In further technical solution, it is connected through a screw thread between the pressing device and connecting sleeve.
In further technical solution, the connecting sleeve outer wall is equipped with annular slot, and the connecting sleeve passes through annular
Card slot is connect with tail bone pipe.
In above scheme, the gap between the protection shell and thin wall cylinder is vacuum state, avoids sensor because locating for
The atmospheric pressure error that height above sea level or geographical location are different and introduce.
In further technical solution, the junction of the thin wall cylinder and protection shell is filled with silicon rubber.
A kind of measurement method for the fiber-optic grating sensor that can measure temperature and pressure simultaneously, by the fiber grating when measurement
Sensor is connected on pipeline to be measured or puts into seawater, so that measured medium enters in the cavity of thin wall cylinder, thin wall cylinder
Pressure difference can generate deformation because inside and outside, and be transmitted on the first fiber grating and the second fiber grating, the first optical fiber light
Grid are shown as the red shift of central wavelength by normal strain, and the second fiber grating shows as central wavelength blue shift.Utilize following decoupling
The temperature and pressure of equation calculation measured medium:
Wherein, KT1, KT2, KP1, KP2The respectively temperature coefficient of the first fiber grating and the second fiber grating and pressure system
Number can be measured by experiment；
Δλ1With Δ λ2It is the central wavelength amount of movement of the first fiber grating and the second fiber grating respectively；
T and P is respectively the temperature and pressure of testing medium.
Through the above technical solutions, the fiber-optic grating sensor provided by the invention that can measure temperature and pressure simultaneously is thin
Wall cylinder is the tubular structure that a kind of section is class ellipse, and the inside of this structure is directly contacted with measured medium, for pressure
Introducing；Outside is in contact with reference pressure medium (vacuumize process), when barrel pressure at both sides difference, can generate on barrel
Strain, the face (front) where the straight flange of the barrel section can be stretched, and the face (side) where the circular arc of section can be shunk,
Cause to be located at what the fiber grating that the strain that positive fiber grating is subject to the increase of pressure increases, and is located at side was subject to
Strain then reduces.Two fiber gratings cause wavelength that different movements, two optical fiber occur because of fixed position deformation behavior difference
Pressure characteristic between grating has differences.After the temperature and the pressure characteristic that obtain two fiber gratings, pass through data processing
Acquisition while temperature and pressure data can be realized.
The advantages of fiber-optic grating sensor of the invention, is: enhanced sensitivity caused by shape of the present invention by improving thin wall cylinder
Structure improves the pressure-sensitivity of sensor；Two fiber gratings are axially fixed in thin-walled drum outer wall central location, are mentioned
The high temperature consistency and response speed of two fiber gratings；It is asked by the sealing that Graphite pad solves at tail optical fiber fairlead
Topic, avoid thin wall cylinder and protect shell between blank medium (present invention is the influence vacuumized) by outside pressure, is mentioned
The high watertightness of sensor, to improve the environmental suitability of sensor.
It is tested by experiment, pressure-sensitivity of the inventive sensor within the scope of 0~1Mpa reaches 1.198nm/MPa, solution
It has determined Temperature cross-over tender subject, has realized the synchro measure of temperature and pressure；And sensor of the invention encapsulates watertightness
It is good, it can be applied not only to the measurement of pipeline pressure, can also be applied to seawater pressure measurement, and then according to sea water advanced and pressure
Linear corresponding relation, obtain sea water advanced numerical value.The sensor application occasion is extensive, and market potential is huge.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described.
Fig. 1 is the fiber-optic grating sensor axial direction that one kind disclosed in the embodiment of the present invention can measure temperature and pressure simultaneously
Cross-sectional view；
Fig. 2 is thin wall cylinder schematic perspective view disclosed in the embodiment of the present invention；
Fig. 3 is the sensitivity test comparison diagram of sensor；
Fig. 4 is pipeline pressure test comparison chart；
Fig. 5 is pipeline pressure test error distribution map.
In figure, 1, thin wall cylinder；2, shell is protected；3, the first fiber grating；4, the second fiber grating；5, positive grating slot；
6, side grating slot；7, annular fixed disk；8, pressure fixing hole；9, threaded hole；10, tail optical fiber fairlead；11, pressing device；12,
Graphite sealing gasket；13, connecting sleeve；14, tail bone pipe；15, optical fiber pigtail；16, annular slot；17, bolt connecting hole.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description.
The fiber-optic grating sensor of temperature and pressure can be measured simultaneously the present invention provides one kind, structure as shown in Figure 1,
The sensor structure is novel, high sensitivity, and temperature decouples fast response time, and measurement result is more acurrate.
One kind as shown in Figure 1 can measure the fiber-optic grating sensor of temperature and pressure simultaneously, including the thin of bottom opening
Wall cylinder 1, the protection shell 2 being encapsulated in outside thin wall cylinder 1, there are gaps between thin wall cylinder 1 and protection shell 2；1 appearance of thin wall cylinder
Face is fixed with the first fiber grating 3 and the second fiber grating 4, the optical fiber pigtail 15 of the first fiber grating 3 and the second fiber grating 4
It is pierced by the top of protection shell 2.In the present embodiment, thin wall cylinder 1 selects metallic copper to be made, and protection shell 2 is stainless steel
Matter.
As shown in Fig. 2, the cross section of thin wall cylinder 1 is by two straight lines and to be separately connected two of two straight line both ends
The class ellipse that semi arch surrounds, the outer surface of thin wall cylinder 1 are equipped with positive grating slot 5 and side grating slot 6, the first optical fiber light
In the positive grating slot 5 in the center in face where grid 3 are fixed on the straight line of thin wall cylinder 1 along the axis direction of thin wall cylinder 1, the second light
In the side grating slot 6 in the center in face where fine grating 4 is fixed on the semi arch of thin wall cylinder 1 along the axis direction of thin wall cylinder 1, and
The center of first fiber grating 3 and the second fiber grating 4 and the center of thin wall cylinder 1 are located on sustained height.
1 bottom outer-edge of thin wall cylinder is connected with annular fixed disk 7, and protection 2 bottom outer-edge of shell is groove structure, annular
Fixed disk 7 is embedded in groove, and is connected between the two by bolt connecting hole 17 disposed thereon, annular fixed disk 7
Pressure fixing hole 8 is opened up in protection 2 bottom outer-edge same position of shell, sensor can be fixed on pressure checking with bolt
On platform, the test of temperature coefficient and pressure coefficient for sensor.
Threaded hole 9 is opened up at the top of protection shell 2,9 bottom of threaded hole opens up the tail optical fiber fairlead 10 with gap connection, screw thread
It has been connected through a screw thread pressing device 11 in hole 9, has been equipped with graphite sealing gasket 12 between 9 bottom of pressing device 11 and threaded hole,
11 rear end of pressing device connects tail bone pipe 14 by connecting sleeve 13, and optical fiber pigtail 15 is pierced by from tail optical fiber fairlead 10, successively
Across graphite sealing gasket 12, pressing device 11, connecting sleeve 13 and tail bone pipe 14.Tail cone pipe 14 draws for optical fiber pigtail 15
Out and it can prevent optical fiber pigtail overbending from fiberoptic light transmission loss being caused to increase.
It is matched, be may be implemented to the effective close of tail optical fiber fairlead with pressing device 11 by using graphite sealing gasket 12
Envelope.Its principle be with pressing device 11 to 12 applied force of graphite sealing gasket when, will lead to graphite sealing gasket 12 and shape occur
Become, and then graphite is full of tail optical fiber fairlead 10, realizes the sealing to tail optical fiber fairlead 10.
In the present embodiment, it is connected through a screw thread between pressing device 11 and connecting sleeve 13；13 outer wall of connecting sleeve is equipped with
Annular slot 16, connecting sleeve 13 are connect by annular slot 16 with tail bone pipe 14.
In above scheme, protecting the gap between shell 2 and thin wall cylinder 1 is vacuum state, avoids sensor because of locating sea
It pulls out or geographical location is different and the atmospheric pressure error that introduces.
The junction of thin wall cylinder 1 and protection shell 2 is filled with silicon rubber, for preventing external substance from surveying into intracavitary influence
Dose-effect fruit.
The manufacturing process of sensor is as follows:
Firstly, carrying out surface cleaning to class ellipse thin wall cylinder 1 using supersonic wave cleaning machine, the can be carried out after cleaning
The fixation of one fiber grating 3 and the second fiber grating 4, in order to guarantee that the first fiber grating 3 and the second fiber grating 4 are in always
Straight condition needs to apply prestressing force to the first fiber grating 3 and the second fiber grating 4 in fixation procedure.Specific method is,
First using the fixed fiber grating one end of glue, the free end for drawing fiber grating is then fallen by counterweight.After fixed fiber grating
The aging process (80 DEG C of constant temperature are handled 10 hours in usual insulating box) for needing to carry out sensor certain time senses to stablize
The characteristic of device.Then one layer of silicon rubber is coated in the outer wall of thin wall cylinder 1, is caused admittedly for preventing water from directly contacting with solidified glue
The failure of tensol.The acquisition of advanced line sensor pressure and temperature characteristic before encapsulation, determines the pressure of two fiber gratings
The encapsulation of sensor is carried out after power and temperature coefficient again.When shell 2 is protected in assembling, protection shell 2 and thin wall cylinder 1 are contacted into position
It sets and coats some silicon rubber, for ensuring the sealing of thin wall cylinder 1 and the gap for protecting shell 2 to be formed.
By graphite sealing gasket 12 be placed in protection 2 tail portion of shell threaded hole 9 in, by pressing device 11 by screw thread with
The protection cooperation of shell 2 draws optical fiber pigtail 15 from tail optical fiber fairlead 10, is then placed into vacuum tank, it is ensured that thin wall cylinder 1
It is vacuum between the chamber formed between protection shell 2, pressing device 11 is tightened by spanner in vacuum tank.
Connecting sleeve 13 is fixed on to the tail portion of pressing device 11, also applied in fixed process some silicon rubber ensure it is close
Envelope.Optical fiber pigtail 15 is drawn from connecting sleeve 13, the yellow set of 900 μm of Loose tubes, 3.0mm are successively set on optical fiber pigtail 15
Pipe and tail cone pipe 14, the protection for optical fiber pigtail.In order to absolutely ensure vacuum degree, it is proposed that this step carries out in vacuum tank.
The class ellipse thin wall cylinder 1 used in the present invention has pressure-sensitivity height, temperature-responsive compared to thin-walled cylinder
Advantage fast rapidly, consistency is good.When measuring pressure, pressure difference will lead to barrel deformation occurs inside and outside barrel, when
When using Circular Thin cylinder, because circular cross-section is respectively to uniform force (circular cross-section is stronger to the restraining force of all directions), because
And section is each all identical to deformation；When using class ellipse thin wall cylinder 1, because of the unevenness of cross sectional shape, cause it is each to
Stress condition it is not identical (class elliptic cross-section is weaker to the constraint opposing circular of all directions), the deformation journey of a front surface and a side surface
Degree is different, and using the feature, multiple responses to same pressure, but also identical pressure can be not only obtained on the different location of barrel
Largest deformation amount under difference also have a distinct increment relative to cylindrical structure (i.e. by same pressure, Circular Thin cylinder respectively to by
Power is uniform, therefore deformation quantity is also identical；Class ellipse thin wall cylinder 1 is respectively to discontinuity, therefore deformation quantity is also
Different, in cross section straight flange center, deformation quantity is maximum, and in arc-shaped edges center, deformation quantity is minimum).
Because temperature and pressure can simultaneously have an impact the center reflection wavelength of fiber grating, how temperature is solved
Cross coupling effect with pressure is the major issue for determining fiber-optic grating sensor measurement accuracy.Two optical fiber in the present invention
Raster center height and position coincides, thus the temperature field locating for them is almost the same.Since two fiber gratings are on barrel
Fixation position be respectively deformation quantity maximum and minimum place, and different location compression deformation difference in thin wall cylinder 1, therefore two
It is also different that strain occurs for fiber grating.
According to principles above, one kind of the invention can measure the measurement side of the fiber-optic grating sensor of temperature and pressure simultaneously
Method is as follows: the fiber-optic grating sensor being connected on pipeline to be measured or is put into seawater when measurement, so that measured medium
Into in the cavity of thin wall cylinder 1, the pressure difference because inside and outside of thin wall cylinder 1 can generate deformation, and be transmitted to the first fiber grating 3
On the second fiber grating 4, the first fiber grating 3 is shown as the red shift of central wavelength, 4 table of the second fiber grating by normal strain
It is now center wavelength blue shift；Utilize the temperature and pressure of following decoupling equation calculation measured medium:
Wherein, KT1, KT2, KP1, KP2The respectively temperature coefficient of the first fiber grating 3 and the second fiber grating 4 and pressure system
Number can be measured by experiment；
Δλ1With Δ λ2It is the central wavelength amount of movement of the first fiber grating 3 and the second fiber grating 4 respectively；
T and P is respectively the temperature and pressure of testing medium.
Performance test experiment:
By the sensor carry out pressure characteristic test, with the patent (publication number: CN101266179) in background technique with
And bibliography (Novel integrated optical fiber sensor for temperature, pressure and
Flow measurement, DOI:10.1016/j.sna.2018.07.034) it compares, obtained central wavelength amount of movement
Curve between the pressure difference of thin wall cylinder two sides is as shown in Figure 3.Pressure sensitive of the inventive sensor within the scope of 0~1Mpa
Degree reaches 1.198nm/MPa, and contrast material is consistent, wall thickness is identical and the thin-walled cylinder pressure sensor of adjoining dimensions is (with reference to text
Offer), pressure-sensitivity improves 7.6 times, and (pressure-sensitivity of patent CN101266179 is 0.033nm/MPa, bibliography
Pressure-sensitivity be 0.158nm/MPa).
The sensor is connected on pressure pipeline and the pressure gauge of standard is carried out than surveying, than surveying effect such as Fig. 4 and Fig. 5 institute
Show, by the test of pressure lifting journey, has obtained the error point of the relationship and sensor between normal pressure and observed pressure
Cloth.As can be seen that the precision of sensor is 1%F.S., and error is in ± 0.01MPa in 0-1MPa pressure limit.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be readily apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to the embodiments shown herein, and is to fit to and the principles and novel features disclosed herein phase one
The widest scope of cause.
Claims (8)
1. one kind can measure the fiber-optic grating sensor of temperature and pressure simultaneously, thin wall cylinder including bottom opening, be encapsulated in it is thin
Protection shell outside wall cylinder, there are gaps between the thin wall cylinder and protection shell；The thin wall cylinder outer surface is fixed with
The optical fiber pigtail of one fiber grating and the second fiber grating, first fiber grating and the second fiber grating is pierced by protection shell
Top, which is characterized in that the cross section of the thin wall cylinder is by two straight lines and being separately connected two straight line both ends
The class ellipse that two semi arches surround, first fiber grating are fixed on the straight line of thin wall cylinder along the axis direction of thin wall cylinder
The center in face where side, face where second fiber grating is fixed on the semi arch of thin wall cylinder along the axis direction of thin wall cylinder
Center, and the center at the center and thin wall cylinder of the first fiber grating and the second fiber grating is located on sustained height.
2. the fiber-optic grating sensor that one kind according to claim 1 can measure temperature and pressure simultaneously, which is characterized in that
The thin wall cylinder bottom outer-edge is connected with annular fixed disk, and the protection outer casing bottom outer rim is groove structure, the ring
Shape fixed disk is embedded in the groove, and is bolted between the two, outside the annular fixed disk and protection outer casing bottom
Pressure fixing hole is opened up in edge same position.
3. the fiber-optic grating sensor that one kind according to claim 1 can measure temperature and pressure simultaneously, which is characterized in that
The protection cover top portion opens up threaded hole, and the threaded hole bottom opens up the tail optical fiber fairlead with the gap connection, described
It has been connected through a screw thread pressing device in threaded hole, graphite sealing gasket is equipped between the pressing device and threaded hole bottom,
The pressing device rear end connects tail bone pipe by connecting sleeve, and the optical fiber pigtail is pierced by from tail optical fiber fairlead, successively wears
Cross graphite sealing gasket, pressing device, connecting sleeve and tail bone pipe.
4. the fiber-optic grating sensor that one kind according to claim 3 can measure temperature and pressure simultaneously, which is characterized in that
It is connected through a screw thread between the pressing device and connecting sleeve.
5. the fiber-optic grating sensor that one kind according to claim 3 can measure temperature and pressure simultaneously, which is characterized in that
The connecting sleeve outer wall is equipped with annular slot, and the connecting sleeve is connect by annular slot with tail bone pipe.
6. the fiber-optic grating sensor that one kind according to claim 1 can measure temperature and pressure simultaneously, which is characterized in that
Gap between the protection shell and thin wall cylinder is vacuum state.
7. the fiber-optic grating sensor that one kind according to claim 2 can measure temperature and pressure simultaneously, which is characterized in that
The junction of the thin wall cylinder and protection shell is filled with silicon rubber.
8. one kind can measure the measurement method of the fiber-optic grating sensor of temperature and pressure simultaneously as described in claim 1,
It is characterized in that, which is connected on pipeline to be measured or puts into seawater by when measurement, so that tested be situated between
Matter enters in the cavity of thin wall cylinder, and thin wall cylinder pressure difference because inside and outside can generate deformation, and be transmitted to the first fiber grating
On the second fiber grating, the first fiber grating is shown as the red shift of central wavelength, the performance of the second fiber grating by normal strain
For center wavelength blue shift；Utilize the temperature and pressure of following decoupling equation calculation measured medium:
Wherein, KT1, KT2, KP1, KP2The temperature coefficient and pressure coefficient of respectively the first fiber grating and the second fiber grating lead to
Crossing experiment can measure；
Δλ1With Δ λ2It is the central wavelength amount of movement of the first fiber grating and the second fiber grating respectively；
T and P is respectively the temperature and pressure of testing medium.
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